CTH12-5: Acquisition Performance Comparison of Transmitted-Reference and Coherent UWB Receivers

Author(s):  
Ning He ◽  
Cihan Tepedelenlioglu
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yu Min Hwang ◽  
Eun Cheol Kim ◽  
Jin Young Kim

This paper presents performance and its simulation results of pseudonoise (PN) code acquisition scheme with MIMO scheme for an ultra-wideband time-hopping/code-division-multiple-access (UWB TH/CDMA) system. The transmission channel is modelled as a frequency selective lognormal fading channel. In almost practical PN code acquisition system, the existence of more than two synchronous cells in the uncertainty region of the search process is possible due to multipath effect. Therefore, based on deriving the detection probability, false alarm rate, miss detection probability, and mean acquisition time, the acquisition performance is analyzed under the hypothesis of multiple synchronous states (cells) in the uncertainty region of the PN code. And the code acquisition performance is evaluated when the correlator outputs are noncoherently combined by using equal gain combining (EGC) scheme. In this procedure, the closed form for the conditional probability of decision variable is derived using the Gauss-Hermite quadrature formula. The performance comparison of the scheme mentioned above shows that the code acquisition performance with the diversity combining technique, especially when increasing the number of antenna, is more robust than that using no diversity. And code acquisition performance comparison also shows that if the detection threshold is set inappropriately, the performance might be degraded, even if an antenna diversity method is applied. It is also shown that Tx diversity can improve the acquisition performance but not as much as Rx diversity does. And Rx diversity can be applied to the acquisition system for additional diversity gain if the complexity of the receiver can be accepted.


Author(s):  
Molla Asmare ◽  
Mustafa Ilbas

Nowadays, the most decisive challenges we are fronting are perfectly clean energy making for equitable and sustainable modern energy access, and battling the emerging alteration of the climate. This is because, carbon-rich fuels are the fundamental supply of utilized energy for strengthening human society, and it will be sustained in the near future. In connection with this, electrochemical technologies are an emerging and domineering tool for efficiently transforming the existing scarce fossil fuels and renewable energy sources into electric power with a trivial environmental impact. Compared with conventional power generation technologies, SOFC that operate at high temperature is emerging as a frontrunner to convert the fuels chemical energy into electric power and permits the deployment of varieties of fuels with negligible ecological destructions. According to this critical review, direct ammonia is obtained as a primary possible choice and price-effective green fuel for T-SOFCs. This is because T-SOFCs have higher volumetric power density, mechanically stable, and high thermal shocking resistance. Also, there is no sealing issue problem which is the chronic issues of the planar one. As a result, the toxicity of ammonia to use as a fuel is minimized if there may be a leakage during operation. It is portable and manageable that can be work everywhere when there is energy demand. Besides, manufacturing, onboard hydrogen deposition, and transportation infrastructure connected snags of hydrogen will be solved using ammonia. Ammonia is a low-priced carbon-neutral source of energy and has more stored volumetric energy compared with hydrogen. Yet, to utilize direct NH3 as a means of hydrogen carrier and an alternative green fuel in T-SOFCs practically determining the optimum operating temperatures, reactant flow rates, electrode porosities, pressure, the position of the anode, thickness and diameters of the tube are still requiring further improvement. Therefore, mathematical modeling ought to be developed to determine these parameters before planning for experimental work. Also, a performance comparison of AS, ES, and CS- T-SOFC powered with direct NH3 will be investigated and best-performed support will be carefully chosen for practical implementation and an experimental study will be conducted for verification based on optimum parameter values obtained from numerical modeling.


1999 ◽  
Author(s):  
C-C. Chen ◽  
C. Lai ◽  
T. Shih

2004 ◽  
Author(s):  
C. Chen ◽  
K. Chang ◽  
T. Lin ◽  
C. Hsu ◽  
Y. Lee ◽  
...  

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